The present invention relates to fire extinguishers, and more particularly to a novel fitting which may be interconnected between a pressure gauge and a port leading to the interior of the fire extinguisher for automatically releasing the extinguisher's contents upon the container-surrounding environment reaching a predetermined temperature.
A typical fire extinguisher includes a cylindrical container for storing fire retardant material under pressure and includes a top portion to which is mounted a manually actuated release mechanism for releasing the extinguisher's contents through a nozzle. The release mechanism generally includes a handle which is pivotally mounted on a nozzle head such that movement of the handle opens a port extending from the container's interior through the spray nozzle to permit the contents to be expelled from such nozzle. The usual fire extinguisher additionally includes a pressure gauge connected to the extinguisher's container so as to display the internal pressure of the container.
It is known to provide so-called fusible link devices on the discharge nozzle of a fire extinguisher to permit release of the extinguisher's contents upon the reaching of a predetermind temperature. For instance, in U.S. Pat. No. 2,824,614 there is disclosed a modified form of a fire extinguisher in which a container includes a dispensing spout having a discharge passage extending therethrough. A plate is secured against the free end of the spout by a fusible agent to close the outer end of the passage. The operation of this fusible agent device is automatic when the device is subjected to enough heat to melt the fusible agent and thereby release the plate therefrom. A knob is also carried by the aforementioned plate to provide a means for facilitating the manual removal of the plate when so desired. However, it is apparent that upon manual removal of such plate, all of the extinguisher's contents would be released. There is no provision in this patent for the selective removal of an extinguisher's contents through manual actuation while still retaining a capability for the extinguisher to automatically release its contents.
Another patent of interest is U.S. Pat. No. 3,273,652 which describes a fire extinguisher including a pressurized chamber provided with a fusible head disposed on a valve through which the container's contents may be released. There is no provision in this patent for manual release of the pressurized contents independently of a release mechanism actuated by the fusible element.
From the above, it can be seen that it would be desirable to modify a fire extinguisher so that such extinguisher could be actuated both manually and by means of a fusible element. Howver, it is also desirable to have a manually actuated valve operable independently of a release mechanism actuated by the reaching of a predetermined temperature. Accordingly, it is a general object of the present invention to provide a fire extinguisher which includes a spray nozzle for releasing contents upon manual actuation and also includes a thermally responsive spray valve automatically actuable to release the contents upon a predetermined temperature being reached.
To provide such a fire extinguisher, the present invention contemplates the use of a spray valve, or more particularly a valve fitting including a normally sealed spray head which is inserted between a pressure gauge and the coupling by which the pressure gauge is normally secured to the extinguisher's container. The valve fitting of the present invention is constructed with a passage extending therethrough to permit pressure from the extinguisher's container to be sensed by the pressure gauge. Disposed on the fitting is a removable spray head including a port extending from the aforementioned passage. The port is normally sealed by a plate or disc which is fused to the spray head by solder or other material having a predetermined melting point.
Thus, the fire extinguisher including the fitting and spray head of the present invention may be situated in an area subject to the outbreak of a fire and may be actuated upon the environment of the area reaching a predetermined temperature. Such areas might include engine compartments of vehicles, boats, and other powered devices as well as various industrial equipment rooms, warehouses, homes, etc. By placing a fire extinguisher using the spray valve of the present invention such that the spray head is directed toward a region susceptible to fire breakout, upon the reaching of a predetermined temperature, the fusible material will melt, thereby automatically releasing the disc from sealing the port so that the pressurized contents will be expelled through such port. Additionally, before such a predetermined temperature is reached, the fire extinguisher may still be manually actuated without interfering with the thermally responsive spray valve.
Another object of the present invention is to provide a retrofit spray valve which may be readily adapted for connection to existing fire extinguishers without substantial modification to such extinguishers.
Yet another object of the present invention is to provide a thermally responsive spray valve mountable on a fire extinguisher independently from the manually actuated valve such that spray expelled from the thermally responsive valve may be selectively directed.
Still a further object of the present invention is to provide a thermally responsive fire extinguisher which may be reused by merely replacing the thermally responsive spray valve and recharging the extinguisher.
These and other objects and attendant advantages of the present invention will become apparent as further consideration is given to the following detailed description and accompanying drawings.